Purbeck Blue MarbleĀ
The most famous of the Purbeck limestones is the Purbeck Marble which has been used for over a thousand years in the building of churches and cathedrals around England. In fact, the Romans first discovered it! Purbeck Marble is not a true marble but a limestone that is strongly cemented and can be polished to a fine finish. It’s composed of nothing but a snail shell callled Viviparus; look closely and you will see their spiral shells cut at many different angles.
The Purbeck Beds formed in shallow swamps and lagoons. At times, some were very brackish or salty and only the hardiest animals could tolerate the conditions. Viviparus was one of those and without competition or predators, their numbers exploded, so much so that they actually make up most of the rock.